1. Field of the Invention
The present invention relates to a glarefoil assembly for reducing headlight glare from oncoming traffic along a divided highway. More particularly, the invention relates to a glarefoil assembly having the novel capability of dissipating energy absorbed from various external sources throughout the entire assembly to decrease the possibility of deformation or failure of the assembly and thus substantially increase its lifetime.
2. Prior Art
The problem of blinding headlight glare along divided highways has resulted in many attempts to reduce this driving hazard. Plants and shrubs have been planted along the top of the median barrier separating the divided lanes to block out the glare from oncoming traffic. This method proved unsatisfactory due to the time-consuming care and attention needed to keep the plants alive and trimmed, as well as the often long waiting periods accompanying the initial growth of the plants. Furthermore, exposure of crew personnel to the high speed traffic of freeway systems creates a severe safety risk while trimming and maintaining foilage.
Another attempt to solve the glare problem consists of an aluminum screen mounted to steel posts along the top of the median barrier. The screen is effective in eliminating headlight glare, but maintenance difficulties make this method impractical. The screens would often come loose and sag when buffeted by the wind and air currents created by passing automobiles. Projecting objects from cars and trucks would often catch the screen and tear large holes or otherwise damage the screen. Such screens were also subject to mischief in the form of thrown objects such as pop bottles or rocks which develop large holes in the screen, necessitating further maintenance. Often in repairing even small holes in the screen, large whose sections of screen had to be replaced, thus adding to labor and material costs.
The screens also created a barrier for police, ambulance and other emergency vehicles and personnel that need quick access across the highway in times of accident or emergency. Often, large holes must be cut in the screen to enable quick response. This not only causes critical delays in treating accident victims and in responding to emergencies, but also necessitates additional cost in later reparations of the screen.
The latest attempt to eliminate the problems caused by the screens resulted in glarefoils which are individually mounted on the top of the median barrier. These glarefoils, sometimes referred to as paddles, are typically elliptical in shape extending up to 4 feet above the median barrier and are commonly made of polyethylene or other thermoplastic material. These glarefoils preserved cross access over the divider and solved some of the maintenance problems associated with the screens. Also, the flexibility of these glarefoils allows them to yield upon impact by protruding or thrown objects and then recover their original shape and position.
Many disadvantages, however, soon became apparent with the individual glarefoil system. Typically, each glarefoil is individually mounted to the median barrier by several bolts. Thus, the installation or removal of each glarefoil is timely and therefore costly. Also, the thermoplastic glarefoils become brittle when exposed to extreme temperatures and ultraviolet radiation from the sun. Furthermore, it has been noted that these glarefoils often break off at the bolt mountings when constantly buffeted by the wind or the everyday air currents from passing cars. Therefore, although the individual glarefoil system helped solve part of the problem of absorbing energy from an occasional random impact they failed to deal with the problem of absorbing the everyday vibrational energy caused by wind and passing cars.
A more detailed description of the prior art has been cataloged and summarized in a publication of the Transportation Research Board of the National Research Counsel in cooperation with the Federal Highway Administration, entitled "Glare Screen Guidelines." This report is dated December 1979 and is available from the Transportation Research Board of the National Academy of Sciences, Washington, D.C. In addition to outlining the various types of glare screen devices, the report lists a number of desirable functions which an effective glare screen should provide. These include:
1. Effectively reduce glare PA1 2. Involve simple installation procedures PA1 3. Be resistant to vandalism and vehicle damage PA1 4. Be adapted for quick and safe repair PA1 5. Require minimal cleaning and painting PA1 6. Incur minimal accumulation of litter and snow PA1 7. Be resistant to winds PA1 8. Provide reasonable cost for purchase and maintenance PA1 9. Include good appearance and provide emergency access to opposing lanes
In addition to the foregoing needs, it should be noted that effective glarefoil assembly must be capable of absorbing and dissipating substantial amounts of vibrational energy which result from the constant everyday buffetings of the wind, as well as impact from vehicles and other objects.